(a) Field of the Invention
The present invention relates to a cooling system for cooling a driving motor of a hybrid vehicle and a method for controlling the same. More particularly, the present invention relates to a cooling system for cooling a driving motor of a hybrid vehicle and a method for controlling the same which supplies suitable cooling flow according to temperature and temperature change rate of the driving motor.
(b) Description of the Related Art
Generally, a hybrid vehicle is a vehicle which uses an engine and a driving motor as power sources. If the driving motor used in the hybrid vehicle is operated, a lot of heat may be generated. The heat generated by the driving motor damages electronic devices sensitive to temperature in the vehicle and deteriorates efficiency of the driving motor. Therefore, suitable cooling flow should be supplied according to temperature change of the driving motor.
Since hydraulic lines for supplying oil to the driving motor are located downstream of a regulating valve according to a cooling system of a conventional hybrid vehicle, the regulating valve controls oil amount so as to maintain line pressure even if engine speed and oil amount discharged from a hydraulic pump increase. Therefore, flow of oil supplied to the hydraulic lines for supplying the oil to the driving motor is generally constant.
In addition, an additional electric oil pump for increasing the oil amount supplied to the driving motor is provided in a cooling system of a conventional hybrid vehicle, but the operational region of the electric oil pump is restricted. That is, the electric oil pump is operated only in a state of initial starting of the vehicle or electric vehicle mode (i.e., a mode at which only the motor is operated). Therefore, the electric oil pump is operated regardless of temperature of the driving motor.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.